Access to data

Conditions of access

A permanent public call for project proposals has been launched. Every research group in France or in other countries, public or private, will be entitled to apply for developing research projects within CONSTANCES after approval by the governing bodies of CONSTANCES: Steering Committee, international Scientific Committee and Ethics Committee. The data transmitted to an external group for a specific study can only be used for the purpose of the study according to the protocol as it was approved by the governing bodies of CONSTANCES and cannot be transmitted to others. The access to the datasets will be free of charge (except for eventual costs related to the extraction of specific data).

This a French cohort, but foreign research groups will be welcomed to analyze CONSTANCES data, so there should be an English version of the database (an English version of the protocol is already available).

Access to data

Ease

downloadable files after agreement.

Conditions of access

A permanent public call for project proposals has been launched. Every research group in France or in other countries, public or private, will be entitled to apply for developing research projects within CONSTANCES after approval by the governing bodies of CONSTANCES: Steering Committee, international Scientific Committee and Ethics Committee. The data transmitted to an external group for a specific study can only be used for the purpose of the study according to the protocol as it was approved by the governing bodies of CONSTANCES and cannot be transmitted to others. The access to the datasets will be free of charge (except for eventual costs related to the extraction of specific data).

This a French cohort, but foreign research groups will be welcomed to analyze CONSTANCES data, so there should be an English version of the database (an English version of the protocol is already available).

Access to data

Ease

downloadable files after agreement.

Conditions of access

A permanent public call for project proposals has been launched. Every research group in France or in other countries, public or private, will be entitled to apply for developing research projects within CONSTANCES after approval by the governing bodies of CONSTANCES: Steering Committee, international Scientific Committee and Ethics Committee. The data transmitted to an external group for a specific study can only be used for the purpose of the study according to the protocol as it was approved by the governing bodies of CONSTANCES and cannot be transmitted to others. The access to the datasets will be free of charge (except for eventual costs related to the extraction of specific data).

This a French cohort, but foreign research groups will be welcomed to analyze CONSTANCES data, so there should be an English version of the database (an English version of the protocol is already available).

Access to data

Ease

downloadable files after agreement.

Conditions of access

A permanent public call for project proposals has been launched. Every research group in France or in other countries, public or private, will be entitled to apply for developing research projects within CONSTANCES after approval by the governing bodies of CONSTANCES: Steering Committee, international Scientific Committee and Ethics Committee. The data transmitted to an external group for a specific study can only be used for the purpose of the study according to the protocol as it was approved by the governing bodies of CONSTANCES and cannot be transmitted to others. The access to the datasets will be free of charge (except for eventual costs related to the extraction of specific data).

This a French cohort, but foreign research groups will be welcomed to analyze CONSTANCES data, so there should be an English version of the database (an English version of the protocol is already available).

Access to data

Ease

downloadable files after agreement.

Conditions of access

A permanent public call for project proposals has been launched. Every research group in France or in other countries, public or private, will be entitled to apply for developing research projects within CONSTANCES after approval by the governing bodies of CONSTANCES: Steering Committee, international Scientific Committee and Ethics Committee. The data transmitted to an external group for a specific study can only be used for the purpose of the study according to the protocol as it was approved by the governing bodies of CONSTANCES and cannot be transmitted to others. The access to the datasets will be free of charge (except for eventual costs related to the extraction of specific data).

This a French cohort, but foreign research groups will be welcomed to analyze CONSTANCES data, so there should be an English version of the database (an English version of the protocol is already available).

Access to data

Ease

downloadable files after agreement.

Conditions of access

A permanent public call for project proposals has been launched. Every research group in France or in other countries, public or private, will be entitled to apply for developing research projects within CONSTANCES after approval by the governing bodies of CONSTANCES: Steering Committee, international Scientific Committee and Ethics Committee. The data transmitted to an external group for a specific study can only be used for the purpose of the study according to the protocol as it was approved by the governing bodies of CONSTANCES and cannot be transmitted to others. The access to the datasets will be free of charge (except for eventual costs related to the extraction of specific data).

This a French cohort, but foreign research groups will be welcomed to analyze CONSTANCES data, so there should be an English version of the database (an English version of the protocol is already available).

Coverage

Years of collection, reference years, and sample sizes

The CONSTANCES cohort will be a large sample of 200,000 individuals aged 18-69 at inception, included over a five-year period (2012-2016). The duration of follow-up will be as long as possible. Three kinds of data will be collected: annual self-administered questionnaire, medical visit (at inclusion and every 5 years) and regular linkage with SNIIR-AM, CNAV and CépiDC national databases (see below for a description of these databases).

First year of collection

The first participants have been recruited in 2012 (approximately 20,000 during this first year).

Base used for sampling

The base used for the random sampling is the register of all French adults affiliated to the General Health Insurance Fund (about 85% of the general population), aged 18-69, and living in one of the 16 selected districts (districts located in different regions of France).

Geographical coverage and breakdowns

The geographical coverage is incomplete: only 16 districts out of 96 are participating. Nevertheless, the structure of the population for these 16 districts is essentially identical to that of France as a whole for the principal demographic, social, and occupational characteristics.

Age range

Population aged 18-69 at inception.

Coverage of main and cross-cutting topics

Data collected will allow for a detailed study of health, wellbeing (medical examination & biological specimens, scales measuring cognitive and physical functioning, including ability to use new technologies, and a specific scale measuring quality of life for senior citizens) and occupational issues (job history; postural, mechanical and organizational constraints; stress at work…). Standard social and demographic characteristics will be collected: social position, educational and income level, employment and marital status, household composition, socioeconomic status of parents and spouse, and material living conditions (type of housing, household income…), including geocoding of the residency address.
If necessary, additional information can be collected when needed for nested projects (either on the whole cohort or on subsets of subjects), but these projects will have to pay corresponding additional costs.

Coverage

Years of collection, reference years, and sample sizes

The CONSTANCES cohort will be a large sample of 200,000 individuals aged 18-69 at inception, included over a five-year period (2012-2016). The duration of follow-up will be as long as possible. Three kinds of data will be collected: annual self-administered questionnaire, medical visit (at inclusion and every 5 years) and regular linkage with SNIIR-AM, CNAV and CépiDC national databases (see below for a description of these databases).

First year of collection

The first participants have been recruited in 2012 (approximately 20,000 during this first year).

Base used for sampling

The base used for the random sampling is the register of all French adults affiliated to the General Health Insurance Fund (about 85% of the general population), aged 18-69, and living in one of the 16 selected districts (districts located in different regions of France).

Geographical coverage and breakdowns

The geographical coverage is incomplete: only 16 districts out of 96 are participating. Nevertheless, the structure of the population for these 16 districts is essentially identical to that of France as a whole for the principal demographic, social, and occupational characteristics.

Age range

Population aged 18-69 at inception.

Coverage of main and cross-cutting topics

Data collected will allow for a detailed study of health, wellbeing (medical examination & biological specimens, scales measuring cognitive and physical functioning, including ability to use new technologies, and a specific scale measuring quality of life for senior citizens) and occupational issues (job history; postural, mechanical and organizational constraints; stress at work…). Standard social and demographic characteristics will be collected: social position, educational and income level, employment and marital status, household composition, socioeconomic status of parents and spouse, and material living conditions (type of housing, household income…), including geocoding of the residency address.
If necessary, additional information can be collected when needed for nested projects (either on the whole cohort or on subsets of subjects), but these projects will have to pay corresponding additional costs.

Coverage

Years of collection, reference years, and sample sizes

The CONSTANCES cohort will be a large sample of 200,000 individuals aged 18-69 at inception, included over a five-year period (2012-2016). The duration of follow-up will be as long as possible. Three kinds of data will be collected: annual self-administered questionnaire, medical visit (at inclusion and every 5 years) and regular linkage with SNIIR-AM, CNAV and CépiDC national databases (see below for a description of these databases).

First year of collection

The first participants have been recruited in 2012 (approximately 20,000 during this first year).

Base used for sampling

The base used for the random sampling is the register of all French adults affiliated to the General Health Insurance Fund (about 85% of the general population), aged 18-69, and living in one of the 16 selected districts (districts located in different regions of France).

Geographical coverage and breakdowns

The geographical coverage is incomplete: only 16 districts out of 96 are participating. Nevertheless, the structure of the population for these 16 districts is essentially identical to that of France as a whole for the principal demographic, social, and occupational characteristics.

Age range

Population aged 18-69 at inception.

Coverage of main and cross-cutting topics

Data collected will allow for a detailed study of health, wellbeing (medical examination & biological specimens, scales measuring cognitive and physical functioning, including ability to use new technologies, and a specific scale measuring quality of life for senior citizens) and occupational issues (job history; postural, mechanical and organizational constraints; stress at work…). Standard social and demographic characteristics will be collected: social position, educational and income level, employment and marital status, household composition, socioeconomic status of parents and spouse, and material living conditions (type of housing, household income…), including geocoding of the residency address.
If necessary, additional information can be collected when needed for nested projects (either on the whole cohort or on subsets of subjects), but these projects will have to pay corresponding additional costs.

Coverage

Years of collection, reference years, and sample sizes

The CONSTANCES cohort will be a large sample of 200,000 individuals aged 18-69 at inception, included over a five-year period (2012-2016). The duration of follow-up will be as long as possible. Three kinds of data will be collected: annual self-administered questionnaire, medical visit (at inclusion and every 5 years) and regular linkage with SNIIR-AM, CNAV and CépiDC national databases (see below for a description of these databases).

First year of collection

The first participants have been recruited in 2012 (approximately 20,000 during this first year).

Base used for sampling

The base used for the random sampling is the register of all French adults affiliated to the General Health Insurance Fund (about 85% of the general population), aged 18-69, and living in one of the 16 selected districts (districts located in different regions of France).

Geographical coverage and breakdowns

The geographical coverage is incomplete: only 16 districts out of 96 are participating. Nevertheless, the structure of the population for these 16 districts is essentially identical to that of France as a whole for the principal demographic, social, and occupational characteristics.

Age range

Population aged 18-69 at inception.

Coverage of main and cross-cutting topics

Data collected will allow for a detailed study of health, wellbeing (medical examination & biological specimens, scales measuring cognitive and physical functioning, including ability to use new technologies, and a specific scale measuring quality of life for senior citizens) and occupational issues (job history; postural, mechanical and organizational constraints; stress at work…). Standard social and demographic characteristics will be collected: social position, educational and income level, employment and marital status, household composition, socioeconomic status of parents and spouse, and material living conditions (type of housing, household income…), including geocoding of the residency address.
If necessary, additional information can be collected when needed for nested projects (either on the whole cohort or on subsets of subjects), but these projects will have to pay corresponding additional costs.

Coverage

Years of collection, reference years, and sample sizes

The CONSTANCES cohort will be a large sample of 200,000 individuals aged 18-69 at inception, included over a five-year period (2012-2016). The duration of follow-up will be as long as possible. Three kinds of data will be collected: annual self-administered questionnaire, medical visit (at inclusion and every 5 years) and regular linkage with SNIIR-AM, CNAV and CépiDC national databases (see below for a description of these databases).

First year of collection

The first participants have been recruited in 2012 (approximately 20,000 during this first year).

Base used for sampling

The base used for the random sampling is the register of all French adults affiliated to the General Health Insurance Fund (about 85% of the general population), aged 18-69, and living in one of the 16 selected districts (districts located in different regions of France).

Geographical coverage and breakdowns

The geographical coverage is incomplete: only 16 districts out of 96 are participating. Nevertheless, the structure of the population for these 16 districts is essentially identical to that of France as a whole for the principal demographic, social, and occupational characteristics.

Age range

18-69 at inception.

Coverage of main and cross-cutting topics

Please specify in no more than 1,200 characters with spaces (approx. twelve lines).
Data collected will allow for a detailed study of health, wellbeing (medical examination & biological specimens, scales measuring cognitive and physical functioning, including ability to use new technologies, and a specific scale measuring quality of life for senior citizens) and occupational issues (job history; postural, mechanical and organizational constraints; stress at work…). Standard social and demographic characteristics will be collected: social position, educational and income level, employment and marital status, household composition, socioeconomic status of parents and spouse, and material living conditions (type of housing, household income…), including geocoding of the residency address.
If necessary, additional information can be collected when needed for nested projects (either on the whole cohort or on subsets of subjects), but these projects will have to pay corresponding additional costs.

Coverage

Years of collection, reference years, and sample sizes

The CONSTANCES cohort will be a large sample of 200,000 individuals aged 18-69 at inception, included over a five-year period (2012-2016). The duration of follow-up will be as long as possible. Three kinds of data will be collected: annual self-administered questionnaire, medical visit (at inclusion and every 5 years) and regular linkage with SNIIR-AM, CNAV and CépiDC national databases (see below for a description of these databases).

First year of collection

The first participants have been recruited in 2012 (approximately 20,000 during this first year).

Base used for sampling

The base used for the random sampling is the register of all French adults affiliated to the General Health Insurance Fund (about 85% of the general population), aged 18-69, and living in one of the 16 selected districts (districts located in different regions of France).

Geographical coverage and breakdowns

The geographical coverage is incomplete: only 16 districts out of 96 are participating. Nevertheless, the structure of the population for these 16 districts is essentially identical to that of France as a whole for the principal demographic, social, and occupational characteristics.

Age range

18-69 at inception.

Coverage of main and cross-cutting topics

Data collected will allow for a detailed study of health, wellbeing (medical examination & biological specimens, scales measuring cognitive and physical functioning, including ability to use new technologies, and a specific scale measuring quality of life for senior citizens) and occupational issues (job history; postural, mechanical and organizational constraints; stress at work…). Standard social and demographic characteristics will be collected: social position, educational and income level, employment and marital status, household composition, socioeconomic status of parents and spouse, and material living conditions (type of housing, household income…), including geocoding of the residency address.
If necessary, additional information can be collected when needed for nested projects (either on the whole cohort or on subsets of subjects), but these projects will have to pay corresponding additional costs.

Linkage

Standardisation

Whenever it was possible and pertinent scales already published in the literature were used, for which the psychometric properties are already established.

Possibility of linkage among databases

In addition to the data collected through self-administered questionnaires and medical visits, social & work-related events and health data will be followed up by regular linkage with the following national databases: CNAV database (periods of employment and unemployment, sick leave, maternity leave, various social benefits…), SNIIR-AM (it contains reimbursement data for health professionals visits and prescribed drugs, long-term diseases, hospital discharge records…), CépiDc (for vital status and cause of death).

Linkage

Standardisation

Whenever it was possible and pertinent scales already published in the literature were used, for which the psychometric properties are already established.

Possibility of linkage among databases

In addition to the data collected through self-administered questionnaires and medical visits, social & work-related events and health data will be followed up by regular linkage with the following national databases: CNAV database (periods of employment and unemployment, sick leave, maternity leave, various social benefits…), SNIIR-AM (it contains reimbursement data for health professionals visits and prescribed drugs, long-term diseases, hospital discharge records…), CépiDc (for vital status and cause of death).

Linkage

Standardisation

Whenever it was possible and pertinent scales already published in the literature were used, for which the psychometric properties are already established.

Possibility of linkage among databases

In addition to the data collected through self-administered questionnaires and medical visits, social & work-related events and health data will be followed up by regular linkage with the following national databases: CNAV database (periods of employment and unemployment, sick leave, maternity leave, various social benefits…), SNIIR-AM (it contains reimbursement data for health professionals visits and prescribed drugs, long-term diseases, hospital discharge records…), CépiDc (for vital status and cause of death).

Linkage

Standardisation

Whenever it was possible and pertinent scales already published in the literature were used, for which the psychometric properties are already established.

Possibility of linkage among databases

In addition to the data collected through self-administered questionnaires and medical visits, social & work-related events and health data will be followed up by regular linkage with the following national databases: CNAV database (periods of employment and unemployment, sick leave, maternity leave, various social benefits…), SNIIR-AM (it contains reimbursement data for health professionals visits and prescribed drugs, long-term diseases, hospital discharge records…), CépiDc (for vital status and cause of death).

Linkage

Standardisation

Whenever it was possible and pertinent scales already published in the literature were used, for which the psychometric properties are already established.

Possibility of linkage among databases

In addition to the data collected through self-administered questionnaires and medical visits, social & work-related events and health data will be followed up by regular linkage with the following national databases: CNAV database (periods of employment and unemployment, sick leave, maternity leave, various social benefits…), SNIIR-AM (it contains reimbursement data for health professionals visits and prescribed drugs, long-term diseases, hospital discharge records…), CépiDc (for vital status and cause of death).

Linkage

Standardisation

Whenever it was possible and pertinent scales already published in the literature were used, for which the psychometric properties are already established.

Possibility of linkage among databases

In addition to the data collected through self-administered questionnaires and medical visits, social & work-related events and health data will be followed up by regular linkage with the following national databases: CNAV database (periods of employment and unemployment, sick leave, maternity leave, various social benefits…), SNIIR-AM (it contains reimbursement data for health professionals visits and prescribed drugs, long-term diseases, hospital discharge records…), CépiDc (for vital status and cause of death).

Data quality

Consistency of terminology or coding used during collection

Currently optimal.

Data quality

Breaks

None

Consistency of terminology or coding used during collection

Currently optimal.

Data quality

Consistency of terminology or coding used during collection

Currently optimal.

Data quality

Consistency of terminology or coding used during collection

Currently optimal.

Data quality

Breaks

None.

Consistency of terminology or coding used during collection

Currently optimal.

Data quality

Breaks

None.

Consistency of terminology or coding used during collection

Currently optimal.

Applicability

CONSTANCES has several strengths. It was designed both to help answer research questions in diverse areas and to provide public health information needed by the health authorities. The sample will be large, including persons living and working in diverse settings, from large cities to small villages in different regions of France, with a broad range of socioeconomic statuses and trades, allowing for the study of specific economic and professional categories with a satisfactory power for many analyses. The follow-up will be very extensive, relying both on active participation of the volunteers through annual questionnaires and regular medical visits, and on passive methods through regular linkage to health and socioeconomic national exhaustive databases. Numerous data will be collected, including a comprehensive medical, physiological and biological examination and a large biobank. CONSTANCES collects very detailed data on personal, lifestyle, environmental, behavioural, occupational and social factors using state-of-the-art methods. A unique feature of CONSTANCES is also its inclusion of a comprehensive set of cognitive and physical tests starting as young as 45 years, which is earlier in the life-course than most available studies on aging. Of particular importance is the high frequency of measurements from many different sources, allowing for analyses of life-course trajectories of health in relation to personal, social, occupational factors and major life events. Finally, the application comes from an experienced team that has more than 20 years of expertise in successfully designing, implementing and maintaining GAZEL, a large population-based prospective cohort, and in developing numerous fruitful collaborations with French and international groups.
The project also has some limitations. Due to the voluntary participation of cohort members, there will probably be an underrepresentation of hard-to-reach subjects, such as heavy drinkers or socially excluded persons. Comparisons between participants and non-participants at inclusion and during the follow-up through regular surveys of non-participants and the randomly selected “non-participants cohort” should allow assessment of potential biases due to selection effects.

Applicability

CONSTANCES has several strengths. It was designed both to help answer research questions in diverse areas and to provide public health information needed by the health authorities. The sample will be large, including persons living and working in diverse settings, from large cities to small villages in different regions of France, with a broad range of socioeconomic statuses and trades, allowing for the study of specific economic and professional categories with a satisfactory power for many analyses. The follow-up will be very extensive, relying both on active participation of the volunteers through annual questionnaires and regular medical visits, and on passive methods through regular linkage to health and socioeconomic national exhaustive databases. Numerous data will be collected, including a comprehensive medical, physiological and biological examination and a large biobank. CONSTANCES collects very detailed data on personal, lifestyle, environmental, behavioural, occupational and social factors using state-of-the-art methods. A unique feature of CONSTANCES is also its inclusion of a comprehensive set of cognitive and physical tests starting as young as 45 years, which is earlier in the life-course than most available studies on aging. Of particular importance is the high frequency of measurements from many different sources, allowing for analyses of life-course trajectories of health in relation to personal, social, occupational factors and major life events. Finally, the application comes from an experienced team that has more than 20 years of expertise in successfully designing, implementing and maintaining GAZEL, a large population-based prospective cohort, and in developing numerous fruitful collaborations with French and international groups.
The project also has some limitations. Due to the voluntary participation of cohort members, there will probably be an underrepresentation of hard-to-reach subjects, such as heavy drinkers or socially excluded persons. Comparisons between participants and non-participants at inclusion and during the follow-up through regular surveys of non-participants and the randomly selected “non-participants cohort” should allow assessment of potential biases due to selection effects.

Applicability

CONSTANCES has several strengths. It was designed both to help answer research questions in diverse areas and to provide public health information needed by the health authorities. The sample will be large, including persons living and working in diverse settings, from large cities to small villages in different regions of France, with a broad range of socioeconomic statuses and trades, allowing for the study of specific economic and professional categories with a satisfactory power for many analyses. The follow-up will be very extensive, relying both on active participation of the volunteers through annual questionnaires and regular medical visits, and on passive methods through regular linkage to health and socioeconomic national exhaustive databases. Numerous data will be collected, including a comprehensive medical, physiological and biological examination and a large biobank. CONSTANCES collects very detailed data on personal, lifestyle, environmental, behavioural, occupational and social factors using state-of-the-art methods. A unique feature of CONSTANCES is also its inclusion of a comprehensive set of cognitive and physical tests starting as young as 45 years, which is earlier in the life-course than most available studies on aging. Of particular importance is the high frequency of measurements from many different sources, allowing for analyses of life-course trajectories of health in relation to personal, social, occupational factors and major life events. Finally, the application comes from an experienced team that has more than 20 years of expertise in successfully designing, implementing and maintaining GAZEL, a large population-based prospective cohort, and in developing numerous fruitful collaborations with French and international groups.
The project also has some limitations. Due to the voluntary participation of cohort members, there will probably be an underrepresentation of hard-to-reach subjects, such as heavy drinkers or socially excluded persons. Comparisons between participants and non-participants at inclusion and during the follow-up through regular surveys of non-participants and the randomly selected “non-participants cohort” should allow assessment of potential biases due to selection effects.

Applicability

CONSTANCES has several strengths. It was designed both to help answer research questions in diverse areas and to provide public health information needed by the health authorities. The sample will be large, including persons living and working in diverse settings, from large cities to small villages in different regions of France, with a broad range of socioeconomic statuses and trades, allowing for the study of specific economic and professional categories with a satisfactory power for many analyses. The follow-up will be very extensive, relying both on active participation of the volunteers through annual questionnaires and regular medical visits, and on passive methods through regular linkage to health and socioeconomic national exhaustive databases. Numerous data will be collected, including a comprehensive medical, physiological and biological examination and a large biobank. CONSTANCES collects very detailed data on personal, lifestyle, environmental, behavioural, occupational and social factors using state-of-the-art methods. A unique feature of CONSTANCES is also its inclusion of a comprehensive set of cognitive and physical tests starting as young as 45 years, which is earlier in the life-course than most available studies on aging. Of particular importance is the high frequency of measurements from many different sources, allowing for analyses of life-course trajectories of health in relation to personal, social, occupational factors and major life events. Finally, the application comes from an experienced team that has more than 20 years of expertise in successfully designing, implementing and maintaining GAZEL, a large population-based prospective cohort, and in developing numerous fruitful collaborations with French and international groups.
The project also has some limitations. Due to the voluntary participation of cohort members, there will probably be an underrepresentation of hard-to-reach subjects, such as heavy drinkers or socially excluded persons. Comparisons between participants and non-participants at inclusion and during the follow-up through regular surveys of non-participants and the randomly selected “non-participants cohort” should allow assessment of potential biases due to selection effects.

Applicability

CONSTANCES has several strengths. It was designed both to help answer research questions in diverse areas and to provide public health information needed by the health authorities. The sample will be large, including persons living and working in diverse settings, from large cities to small villages in different regions of France, with a broad range of socioeconomic statuses and trades, allowing for the study of specific economic and professional categories with a satisfactory power for many analyses. The follow-up will be very extensive, relying both on active participation of the volunteers through annual questionnaires and regular medical visits, and on passive methods through regular linkage to health and socioeconomic national exhaustive databases. Numerous data will be collected, including a comprehensive medical, physiological and biological examination and a large biobank. CONSTANCES collects very detailed data on personal, lifestyle, environmental, behavioural, occupational and social factors using state-of-the-art methods. A unique feature of CONSTANCES is also its inclusion of a comprehensive set of cognitive and physical tests starting as young as 45 years, which is earlier in the life-course than most available studies on aging. Of particular importance is the high frequency of measurements from many different sources, allowing for analyses of life-course trajectories of health in relation to personal, social, occupational factors and major life events. Finally, the application comes from an experienced team that has more than 20 years of expertise in successfully designing, implementing and maintaining GAZEL, a large population-based prospective cohort, and in developing numerous fruitful collaborations with French and international groups.
The project also has some limitations. Due to the voluntary participation of cohort members, there will probably be an underrepresentation of hard-to-reach subjects, such as heavy drinkers or socially excluded persons. Comparisons between participants and non-participants at inclusion and during the follow-up through regular surveys of non-participants and the randomly selected “non-participants cohort” should allow assessment of potential biases due to selection effects.

Applicability

CONSTANCES has several strengths. It was designed both to help answer research questions in diverse areas and to provide public health information needed by the health authorities. The sample will be large, including persons living and working in diverse settings, from large cities to small villages in different regions of France, with a broad range of socioeconomic statuses and trades, allowing for the study of specific economic and professional categories with a satisfactory power for many analyses. The follow-up will be very extensive, relying both on active participation of the volunteers through annual questionnaires and regular medical visits, and on passive methods through regular linkage to health and socioeconomic national exhaustive databases. Numerous data will be collected, including a comprehensive medical, physiological and biological examination and a large biobank. CONSTANCES collects very detailed data on personal, lifestyle, environmental, behavioural, occupational and social factors using state-of-the-art methods. A unique feature of CONSTANCES is also its inclusion of a comprehensive set of cognitive and physical tests starting as young as 45 years, which is earlier in the life-course than most available studies on aging. Of particular importance is the high frequency of measurements from many different sources, allowing for analyses of life-course trajectories of health in relation to personal, social, occupational factors and major life events. Finally, the application comes from an experienced team that has more than 20 years of expertise in successfully designing, implementing and maintaining GAZEL, a large population-based prospective cohort, and in developing numerous fruitful collaborations with French and international groups.
The project also has some limitations. Due to the voluntary participation of cohort members, there will probably be an underrepresentation of hard-to-reach subjects, such as heavy drinkers or socially excluded persons. Comparisons between participants and non-participants at inclusion and during the follow-up through regular surveys of non-participants and the randomly selected “non-participants cohort” should allow assessment of potential biases due to selection effects.